RFHCS362G_11 Datasheet, PDF (30/54 Pages) Microchip Technology – KEELOQ® Code Hopping Encoder with UHF ASK/FSK Transmitter

rfHCS362G/362F
FIGURE 6-4: EXAMPLE LOOP FILTER
CIRCUIT
rfHCS362G/362F
LF
R1
C2
C1
TABLE 6-4: EXAMPLE LOOP FILTER VALUES FOR TRANSMIT FREQUENCY = 433.92 MHz ⁽¹⁾
C1
C2
R1
Loop BW
Fn (natural
freq in Hz)
Phase Margin
(not counting
sampling delay)
2nd Order
damping
factor
Calculated
Lock Time
0.01 uF
3900 pF
1500 pF
1000 pF
390 pF
100 pF
47 pF
18 pF
680
1.5K
2.7K
4.7K
165 kHz
360 kHz
610 kHz
1.05 MHz
64 kHz
103 kHz
166 kHz
203 kHz
65 deg
63 deg
55 deg
50 deg
1.37
47 μs
1.89
29 μs
2.10
18 μs
3.0
15 μs
Note 1: Standard Operating Conditions (unless otherwise stated) TA = 25°C, RFEN = 1, VDDRF = 3V.
TABLE 6-5: EXAMPLE LOOP FILTER VALUES FOR TRANSMIT FREQUENCY = 315 MHz ⁽¹⁾
C1
C2
R1
Loop BW
Fn (natural
freq in Hz)
Phase Margin
(not counting
sampling delay)
2nd Order
damping
factor
Calculated
Lock Time
3900 pF 390 pF
680
3900 pF 680 pF
680
3900 pF 1000 pF 680
190 kHz
175 kHz
155 kHz
112 kHz
112 kHz
112 kHz
55 deg
47 deg
39 deg
0.94
27 μs
0.94
27 μs
0.94
27 μs
Note 1: Standard Operating Conditions (unless otherwise stated) TA = 25°C, RFEN = 1, VDDRF = 3V.
DS41189B-page 30
© 2011 Microchip Technology Inc.